The present invention pertains to light duty liquid detergents which are useful for hand washing dishes, pots, pans, glassware, and silverware. The composition additionally finds use as a hand washing composition for delicate clothing. In particular, the invention pertains to a liquid detergent composition including an improved viscosity modifying agent, namely 3-methyl-3-methoxy butanol.
Greasy soils are one of the most difficult types of soils to be removed by hand washing. Effective grease removal is nearly always associated with requiring high temperature water to help dissolve and remove the grease. It would be advantageous to formulate a mild, foaming, liquid hand dish washing composition, which is capable of and effective in removing greasy soils as well as other soil types from dishware using water at ambient or warm to high temperature. It has been known well known in the art to produce liquid detergents to use an aqueous solution of one or more anionic or nonionic surfactants in conjunction with a hydrotrope and a small amount of a viscosity control agent. Viscosity control agents are typically lower aliphatic alcohols such as ethanol and isopropanol. Without such a viscosity modifying agent, the detergent composition would be too thick to be useful. A problem with known viscosity modifying agents is that they have an objectionable odor and furthermore they have relatively high vapor pressures. For example, ethanol is a commonly used viscosity modifying agent, however it has a vapor pressure of approximately 46 mm Hg at 25.degree. C. (CRC Handbook, Pg. D192, R. Weast, ed., CRC Press, Boca Raton, Fla., 1979). States are increasingly limiting the allowable vapor pressure of solvents which can be used in such compositions and it would be advantageous to have an effective viscosity modifying agent having a lower vapor pressure.
The use of solvents in liquid detergent compositions is widely known in the art. U.S. Pat. No. 4,753,750 teaches that the use of ethanol and C.sub.1 -C.sub.4 etheric derivatives of lower polyols such as ethylene glycol as viscosity modifiers is known. The use of ethyl, propyl, butyl and amyl alcohol in cleaning compositions is known from U.S. Pat. Nos. 5,041,235; 5,035,814, 3,856,695 and 4,483,779. Liquid detergents including lower alcohols are shown in U.S. Pat. Nos. 5,008,031 and 4,790,951 and higher alcohols are shown in U.S. Pat. No. 4,732,696. U.S. Pat. No. 4,600,522 shows furfuryl and tetrahydrofurfuryl alcohols. U.S. Pat. No. 4,943,392 shows butoxy propanol and butoxy propoxypropanol and U.S. Pat. No. 4,747,977 shows C.sub.2 -C.sub.6 aliphatic polyols. PCT/GB89/00227 shows C.sub.6 -C16 diols. Viscosity increasing additives such as dialkylethers are shown in U.S. Pat. No. 3,954,660.
It has now been found that 3-methyl-3-methoxy-butanol is exceptionally useful as a viscosity modifier for light duty liquid hand washing compositions. It has the added benefits of having a low odor property and very low vapor pressure, on the order of 0.4 mm Hg. Accordingly, it is an object of this invention to provide light duty liquid hand washing aqueous detergent compositions which have commercially acceptable mildness, foaming, grease cleaning and foam rinseability properties, while using an improved viscosity modifier having low odor and a low vapor pressure.
The present invention provides compositions which accomplish the foregoing objectives and although prepared from otherwise known ingredients, when used in the instant context is capable of achieving a new and beneficial result.